Life-history variation in the short-lived herb Rorippa palustris: The roleof carbon storage

摘要

Carbon storage is commonly found among perennials, but only rarely in annuals. However, many short-lived species may behave as annuals or short-lived perennials depending on the date of germination.photoperiod or disturbance. Due to the trade-off between investments into current reproduction vs.survival, these life-history modes presumably differ in carbon allocation. In this study, we aimed toevaluate how carbon storage is affected by germination date and disturbance in an outdoor pot exper-iment with the short-lived Rorippa palustris. Plants from autumnal and summer cohorts were injured indifferent ontogenetic stages (vegetative, flowering and fruiting) and the starch content in roots wasassessed. Plants from the autumnal cohort invested more carbon into growth and reproduction, whereasplants from the summer cohort invested preferentially into reserves. However, injury changed theallocation pattern: in plants from the autumnal cohort, injury prevented allocation to reproduction andthus injured plants had a larger carbon storage at the end of the season than control plants; injury at theflowering and fruiting stage caused depletion of reserves for regrowth in plants from the summer cohort,resulting in lower starch reserves compared to control plants. We suggest that life-history variation inR. palustris can be caused by changes in its carbon economy: when all resources could not be used forflowering due to weak photoinduction or loss of flowering organs due to injury, part of the resources isstored for over wintering and reproduction in the next year.